www.devco.net by r.i.pienaar

SixXS IPv6 and CentOS

I thought its high time I get to spend some time with IPv6 so I signed up for a static tunnel from sixxs.net, apart from taking some time it's a fairly painless process to get going.

I chose a static tunnel since I am just 9ms from one of their brokers and my machine is up all the time anyway, they have some docs on how to get RedHat machines talking to them but it was not particularly accurate, this is what I did:

You'll get a mail from them listing your details, something like this:

  Tunnel Id          : T21201
  PoP Name           : dedus01 (de.speedpartner [AS34225])
  Your Location      : Gunzenhausen, de
  SixXS IPv6         : 2a01:x:x:x::1/64
  Your IPv6          : 2a01:x:x:x::2/64
  SixXS IPv4         : 91.184.37.98
  Tunnel Type        : Static (Proto-41)
  Your IPv4          : 78.x.x.x

Using this you can now configure your CentOS machine to bring the tunnel up, you need to edit these files:

/etc/sysconfig/network

NETWORKING_IPV6=yes
IPV6_DEFAULTDEV=sit1

/etc/sysconfig/network-scripts/ifcfg-sit1

DEVICE=sit1
BOOTPROTO=none
ONBOOT=yes
IPV6INIT=yes
IPV6_TUNNELNAME="sixxs"
IPV6TUNNELIPV4="91.184.37.98"
IPV6TUNNELIPV4LOCAL="78.x.x.x"
IPV6ADDR="2a01:x:x:x::2/64"
IPV6_MTU="1280"
TYPE=sit

Just replace the values from your email into the files above, once you have this in place reboot or restart your networking and you should see something like this:

% ifconfig sit1
sit1      Link encap:IPv6-in-IPv4 
          inet6 addr: 2a01:x:x:x::2/64 Scope:Global
          inet6 addr: fe80::4e2f:c3c6/128 Scope:Link
          UP POINTOPOINT RUNNING NOARP  MTU:1480  Metric:1
          RX packets:6383 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6431 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:4072476 (3.8 MiB)  TX bytes:921722 (900.1 KiB)

% ping6 -c 3 -n noc.sixxs.net
PING noc.sixxs.net(2001:838:1:1:210:dcff:fe20:7c7c) 56 data bytes
64 bytes from 2001:838:1:1:210:dcff:fe20:7c7c: icmp_seq=0 ttl=57 time=20.2 ms
64 bytes from 2001:838:1:1:210:dcff:fe20:7c7c: icmp_seq=1 ttl=57 time=28.4 ms
64 bytes from 2001:838:1:1:210:dcff:fe20:7c7c: icmp_seq=2 ttl=57 time=20.1 ms

--- noc.sixxs.net ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2008ms
rtt min/avg/max/mdev = 20.181/22.934/28.406/3.869 ms, pipe 2

Since this is a remote machine it took me some time to figure out how to get browsing going through it, but once I reconnected my SSH SOCKS tunnel it immediately became IPv6 aware and were happily routing me to sites like ipv6.google.com.  To do this just run from your desktop:

ssh -D 1080 yourbox.net

Now set your firefox network.proxy.socks_remote_dns setting to true in about:config, and point your browser at localhost:1080 as a socks proxy, your SSH should now work as a perfectly effective ipv4-to-6 gateway.  You can test it by browsing to either the sixxs.net homepage or ipv6.google.com - watch out for the special google logo.

About R.I. Pienaar

Systems Administrator, Consultant, Linux Guy, Automator, Ruby Coder